Orange diamonds are not as rare as the red or green diamonds. Most of the orange diamonds have strong yellow or brown modifiers. Pastel colored orange diamonds are of similar value as pastel pinks & some blues.
To be classified as orange, there must be a complete absence of brown to the stone. This color of orange is called “apricot.” It is unknown what causes this coloration. There are so few actual oranges, especially ones of known mine origin, that it is difficult to study.
Orange diamonds that look like a Halloween pumpkin sell for more than the yellows. An 8.93 fancy intense orange sold for about $1.9 million at Sotheby’s. Oranges with yellowish secondary colors and with just a hint of brown have lower prices.
Enhanced orange colors mimic the natural ones so well that they are difficult to detect. Again, price factor is the main reason we see so many of the enhanced orange colors on the market.